Drill



F. KANGAS March 8, 1938.

DRILL Filed Jan. 29, 1937 M3 m/w V 5 V M3 Patented Mar. 8, 1938 UNITED STATES PATENT OFFICE 2 Claims.

My invention pertains to drill bits, commonly known as jackbits, and is directed to a novel means of detachably securing and locking the same to the drill shank. As these jackbits are used in drilling of solid rock and the like, it is extremely important that they do not become detached from the shank while in use. On the other hand, as jackbits are frequently replaced, it is also of importance that they do not become frozen to the shank so as to make manual removal difiicult.

The object of my invention is to provide a head or bit which, while capable of being securely locked to the shank, may be readily detached or removed therefrom, and which, under no conditions, will become frozen to the shaft.

My invention is illustrated in the attached drawing, wherein like characters indicate like parts throughout the several views:

Fig. 1 is a front elevation of the bit attached to the shaft or shank, some parts being shown by dotted lines;

Fig. 2 is a vertical axial section taken on the line 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken on the line 3--3 of Fig. 1;

Fig. 4 shows the lock segment removed from the bit;

Fig. 5 is a side elevation of the shank with the bit removed; and

Fig. 6 is a view in elevation illustrating the method used in attaching the head or bit to a shank.

Referring to the drawing, the numeral I indicates the head or jackbit and 8 a shaft or shank having an enlarged portion 9 providing a shoulder III. At the free end of the shaft or shank 8 is a diametrical slot II and a peripheral lock slot I2.

Head 1 is shown as provided with an axial socket I3 extending from its upper portion more than midway therethrough. Diametrical rib I4 extends upward from the bottom of socket I3. In its upper portion at the periphery, head or bit I is shown as provided with a radial port I5.

A lock segment I6 carrying lock lug I1 is adapted to encircle the head or bit I with the lock lug Il projecting into and through the port I5, (see Figs. 2, 3, and 6). Lock segment I6,

being of spring steel and extending more than half way around the head or bit I, is under constant tension to embrace the same. Therefore, the lock lug I'I would normally impede the entrance of the free end of shank 8 into the axial socket I3 of the head I. Fig. 6 illustrates a convenient manner of obviating this difficulty. The shank is turned from the position which it will eventually assume when locked in the head, and then, inserted into the head at an angle, thus camming the lock lug I'I backward and allowing the entrance of the shank 8 into the socket I3. When the shank is then turned 90 to the left, with respect to Fig. 6, rib I4 fits into the slot II and lock lug I'I, under the tension of lock segment I6, jumps forward into slot I2, thereby securely locking the same.

Obviously, all that is required to remove the head or bit from the shank is to pull the lock segment I6 slightly outward from the head releasing the lock lug H from the lock slot I2 of the shank 8.

It will be understood that the structure illustrated is capable of modification within the scope of the invention herein disclosed and claimed.

What I claim is:

1. In a device of the kind described, a head having an axial socket and a radial port leading to said socket, a shank telescoped into said socket and having a peripheral lock slot aligned with the port of said head, a spring lock segment therein encompassing more than half of the perimeter of said head and a lock lug carried by said lock segment and adapted to be 35 held by the spring tension of said segment in the aligned port and lock slot of the head and shank to thereby detachably lock the head and shank together, a diametrical rib in the bottom of said socket, and a diametrical slot in the free end of said shank adapted to fit over said rib.

2. The structure defined in claim 1 in which said head is provided with a peripheral groove in which said spring lock segment is arranged to be seated, said shank above said lock notch 45 having an outstanding shoulder that directly engages the upper end of said socket.

FRANCIS KANGAS. 5o 

